Primary achalasia is a rare worldwide disease with prevalence of eight cases per million population. Manometry is considered the gold standard for diagnosis. Achalasia is incurable in that no treatment can restore the neuronal degeneration; therefore, therapy is aimed at opening the poorly relaxed LES. Here we review the evidence which shows that pneumaticdilation (PD) and surgery are equally effective, with PD having a slight edge. We believe that using PD as initial therapy and saving myotomy as a rescue approach is the preferred overall approach.
Achalasia is a primary esophageal motility disorder characterized by absence of esophageal peristalsis and
poor relaxation of the lower esophageal sphincter (LES). Primary achalasia is a rare worldwide disease
with prevalence of eight cases per million population. Absence of peristalsis results from degeneration
of nitric oxide releasing inhibitory neurons in the esophageal wall. Dysphagia is the most common
symptom of achalasia; however, regurgitation and heartburn are frequently present. Manometry
is considered the gold standard for diagnosis. Achalasia is incurable in that no treatment can restore
the neuronal degeneration; therefore, therapy is aimed at opening the poorly relaxed LES. Evidence shows that
pneumaticdilation (PD) and surgery are equally effective, with PD having a slight edge. We believe that
using PD as initial therapy and saving myotomy as a “rescue” approach is the preferred overall approach.
Mohamed Khalaf, MD, Esophageal Motility Research
Fellow Donald O. Castell, MD, Director of the
Esophageal Disorders Program, Digestive Disease
Center, Gastroenterology and Hepatology, Medical
University of South Carolina, Charleston, SC
INTRODUCTION
Disorders of esophageal motility are often
pursued as an explanation for a variety of upper
gastrointestinal symptoms. These include:
dysphagia, regurgitation, heartburn and even non-
cardiac chest pain. Early radiographic contrast studies
demonstrated that many patients with persistent
progressively worsening dysphagia showed a classical
narrow closure at the esophagogastric junction (EGJ),
the so called “bird beak”. Because of the failure of this
segment to relax or open during swallowing the term
achalasia (from the Greek; “without relaxation”) was
applied.
Definition
Achalasia is a primary esophageal motility disorder.
The diagnosis is confirmed manometrically by absence
of esophageal peristalsis and poor relaxation of the
lower esophageal sphincter (LES). The disease is
suggested clinically by dysphagia and regurgitation of
undigested food and; radiographically by esophageal
dilation, with air-fluid level in mid-esophagus and
narrowed esophagogastric junction (EGJ), “bird-beak”
appearance; and endoscopically by dilated esophagus
with retained fluids and undigested food remnants.1-3
Epidemiology
Primary achalasia is a rare disease with prevalence of
eight cases per million population with an incidence of
about 0.3-1.63 per 100,000 per year. The incidence is
equal in both sexes, but higher in older age groups with
the mean age of diagnosis of about 50 years. Also, due
to the chronic nature of the disease, achalasia apparently
has an increasing prevalence with stable incidence with
age4-6
Etiology & Pathogenesis
With the development of accurate intraluminal pressure-
sensing probes in the 1950s not only was the pressure
defect at the EGJ confirmed but the associated loss
of peristalsis was recognized. This helped clarify the
pathophysiology underlying the severe and progressive
symptoms of dysphagia, regurgitation and weight loss
that characterize this entity; worldwide in its occurrence
as THE esophageal motility disorder.
More recent manometric technologies with high
resolution and colourful 3D pressure displays have
expanded awareness of the possibility of 3 distinct
subtypes of achalasia.
Esophageal peristalsis and LES relaxation are
coordinated by the nitric oxide releasing inhibitory
neurons of the myenteric plexus. These neurons
are absent in primary achalasia resulting in absent
peristalsis and defective LES relaxation. The underlying
pathogenesis remains unclear, but recent pathological
and genetic studies attributed the disappearance of
myenteric inhibitory neurons to chronic ganglionitis
resulting from an autoimmune response against these
neurons triggered by an environmental factor likely
viral (particularly HSV-1) in genetically susceptible
individuals. This is supported by observations that found
association between achalasia with HLA-DQ?1, DQa1
and detection of circulating antibodies to the myenteric
neurons. It is worth saying that the end result esophageal
pathology is irreversible. Also, an association was
found with some genetic syndromes like Down and
Allgrove syndrome (also known as triple A syndrome,
i.e. alacrima, achalasia, adrenocorticotropic hormone
deficiency) suggesting the role of genetic factors.7-11
Clinical Picture
Dysphagia is the most common symptom of achalasia
(>90%). Usually, it is for both solid and liquids from
the start. On the other hand, mechanical obstruction
due to malignancy or stricture also leads to progressive
dysphagia, evolving from solids in the beginning to
solids and liquids. Regurgitation and heartburn were
frequently present. Patients are often treated with acid
suppressive medications assuming that these symptoms
are due to gastroesophageal reflux disease (GERD).
Heartburn in achalasia is explained by stasis and of
undigested food in the esophagus secondary to poor
esophageal clearance, rather than by real GERD. This
misdiagnosis and poor response to acid suppressive
medications can lead to the risk that some of these
patients may be advised to have a fundoplication. Other
symptoms of achalasia include weight loss, cough and
chest pain especially in type III achalasia.5,12,13
The Eckardt score14 based on grading of the
achalasia symptoms can be used in the initial evaluation
of the severity of the condition, as well as in the post-
treatment follow up.2 It is calculated by summation of
the corresponding score for each symptom of dysphagia,
regurgitation, and chest pain (with a score of 0 for
absence of symptoms, 1 for occasional symptoms, 2
for daily symptoms, and 3 for symptoms at each meal)
and weight loss (with 0 for no weight loss, 1 for a loss
of <5 kg, 2 for a loss of 5 – 10 kg, and 3 for a loss of
>10 kg).15
There are other conditions that can mimic achalasia
both clinically and on investigations (manometry,
endoscopy, and radiological studies). These conditions
are called pseudoachalasia or secondary achalasia
which is most commonly caused by malignancy at the
EGJ either by invading the esophageal neural plexuses
directly or by paraneoplastic mechanism. Less common
causes are metastatic disease, infection with the
protozoan parasite Trypanosoma cruzi (Chagas disease),
and iatrogenic like post fundoplication and gastric
banding.16,17 Pseudoachalasia should be suspected when
some clinical characters are different ( short duration
of symptoms; advanced age; rapid and marked weight
loss; resistance to passing the endoscope through the
gastroesophageal junction, and expected treatment
outcomes are not achieved. Thus, careful endoscopic
assessment of the gastric cardia on retroflexed view to
rule out malignancy should be done.12
Investigations
Manometry is considered the gold standard for
diagnosis of achalasia. EGD and barium esophagram
are complimentary methods to support the diagnosis
of achalasia and for exclusion of structural lesions.1,18
Achalasia can be diagnosed using conventional or high
resolution (HRM) manometry systems. According to
conventional manometry 2 types of achalasia have
been identified, classic and vigorous. The manometric
criteria of classic achalasia are: (1) absent peristalsis
in the body of the esophagus characterised either by
simultaneous esophageal contractions with amplitudes
<40 mm Hg or by no apparent esophageal contractions
and (2) incomplete relaxation of the LES. Vigorous
achalasia is characterised by simultaneous esophageal
contractions with amplitudes >40 mm Hg. 17
In HRM: achalasia is classified according to the
latest version of the Chicago classification19 into: types
I, II and III. Table 1 shows the diagnostic criteria of the
3 types in comparison to the corresponding description
of the previous conventional classification.
Also, the use of multichannel intraluminal
impedance with esophageal manometry (MII-EM)
allows functional esophageal assessment and identifies
chronic fluid retention. 20
Endoscopy and barium esophagram are essentially used for exclusion of mechanical obstruction and pseudoachalasia due to tumours at the EGJ. EGD findings in achalasia are non-specific; it might show dilated esophagus and food retention in advanced cases. Barium swallow can show these features: (1) dilated esophagus; (2) air-fluid level in the mid- esophagus; and (3) narrowed EGJ giving the classic “bird-beak” appearance. Occassionally, barium study can demonstrate an extreme cork screw appearance indicating esophageal spasm associated with type III (vigorous) achalasia.5,15,21
Computed tomography (CT) and endoscopic
ultrasound (EUS): In cases of suspected pseudoachalasia
for detection of masses, esophageal mural thickening
or infiltrating lesion.16,22
Treatment
Achalasia is an incurable disease in that no treatment
can restore the neuronal degeneration of the esophageal
wall. Therefore, therapy is aimed at opening the poorly
relaxed LES. This will improve the esophageal clearance
and emptying in the upright position by gravity, leading
to symptom relief.23 The treatment options available are:
1. Pharmacological Therapy
Nitrates (isosorbide mononitrate) and calcium channel
blockers (nifedipine) are the most common drugs used
for temporary decrease of the LES pressure. Both causes
smooth muscle relaxation either by increasing the nitric
oxide levels or by blocking the calcium necessary for
smooth muscle contraction. They can achieve short-
term relief of symptoms, however the clinical response
is partial and with decreased efficacy over time.24
Both drugs can cause dizziness, headaches and
pedal edema. These side effects in addition to short
duration of action and decreased efficacy over time
are the primary causes limiting their use to high risk
patient in favor of more effective treatment options
(endoscopic or surgical).25
Some studies showed that phosphodiesterase
inhibitors (Sildenafil) causes significant decrease in
the LES pressure suggesting its use in clinical practice,
nevertheless, comparative studies are lacking.26
2. Botulinum Toxin (Botox)
Botox (BTX) is a potent toxin that inhibits the release of
acetyl choline from nerve endings leading to paralysis
of the innervated muscle. It is injected endoscopically
using a sclerotherapy needle in all four quadrants of the
LES 1-2 cm above the Z- line. The total dose injected
is from 80 – 100 U.27,28
76% of achalasia patients will respond to one Botox
injection with 50 % recurrence of symptoms within 6
months. These studies suggest consideration of a trial of
another injection since 75% of patients can respond to
the second injection.25 Because of this high recurrence
rate; our practice is to use BTX in high risk patients
or in patients refusing or fearing to have pneumatic
dilation or surgical myotomy.
BTX can be tried before proceeding to pneumatic
dilation and also can be given in cases of failed dilation.
Some studies in the surgical literature indicate that BTX
injection before myotomy can lead to increased rate
of surgical failure because of the scarring produced by
the toxin on the LES muscle layer, however evidence
shows that it can be used in cases of surgery failure.29
Contraindications of Botulinum toxin include egg
allergy and Lambert Eaton syndrome. Also it should
be used cautiously in patients receiving aminoglycoside
antibiotics as it can potentiate the toxin effect.30
3. Pneumatic Dilation (PD)
This endoscopic technique aims to produce a controlled
tear in the muscular layer of the LES by forceful
stretching using an air-filled balloon. This method
improves esophageal emptying and so relieves the
symptoms. The most common balloon used for this
purpose is the Rigiflex balloon dilator (Boston Scientific
Corporation, Boston, MA, USA). It is a 10 cm long
balloon made of polyethylene polymer and comes in
3 diameters (30, 35 and 40 mm). The balloon has 4
radiopaque markers helping in identifying the balloon
borders under fluoroscopic guidance; radiopaque
markers at each end of the balloon, and another 2
markers identifying the middle.2,5,31
The technique involves careful endoscopic
examination of the esophagus and to determine the
location and gross appearance of the LES. It may
show puckering and opens by gentle pressure with the
endoscope. If forceful pressure is needed, one should
suspect pseudoachalasia. The EGJ should be examined
carefully with retroflexion inspection of the cardia to
exclude pseudoachalasia. The findings expected to be
in the esophagus are: esophageal dilation and retained
fluid/food residues. The mucosa may show redness,
friability and cracked appearance due to prolonged
stasis.31
After endoscopic examination, we withdraw the
scope and insert the balloon blindly over a Savary wire.
The key of a successful dilation is to accurately place
the balloon across the EGJ while the patient is in the
supine position.25
Our practice is to inflate the balloon to 10 psi. The
duration of inflation is less than 15 seconds, however
it is not as important as observing that the “waist” is
obliterated during fluoroscopy.32
Figures 1 and 2 show fluoroscopy images during
PD procedure.
Then we withdraw the balloon (blood on it indicates
mucosal tear but not necessarily a successful dilation),
and place a NG tube to perform a gastrographin study
under fluoroscopy to detect early perforation.31
Afterwards we put the patient under observation for
2 hours before discharge. We reassess the patient after
one month using the clinical response and the Eckardt
symptom score. If the patient has a score of 3 or less,
we consider this a success; otherwise, we proceed with
dilation using the next larger diameter balloon until
achieving clinical remission.
This approach of graded dilations has a documented
initial clinical remission rate in 90% of patients,
and probability of remaining in remission without
further dilations at 5 and 10 years is 67% and 52%,
respectively. Also, performing repeated dilations on
demand of symptom recurrence increases the 5 and 10
year remission rate to 97% and 93% respectively. It is
our belief that PD is the most cost-effective treatment
for achalasia over a 5-10-year follow up period with
an overall perforation rate of less than 2%.2,25,33
Surgical Cardiomyotomy (Open or Laparoscopic)
Open surgical myotomy was first described by the
German surgeon Ernest Heller.34 Now, it is widely
replaced by the laparoscopic approach which was first
performed by Cuschieri et al.35 Laparoscopic Heller
myotomy (LHM) has the advantages of being less
invasive, lower morbidity and shorter hospital stay
than the open approach. To curtail the resulting reflux,
addition of a partial fundoplication (Dor or Toupet)
rather than a full Nissen fundoplication as an anti-reflux
procedure shows good results with less postoperative
GERD and dysphagia.36
Successful esophageal myotomy lowers LES
pressure by up to 75%, markedly improves esophageal
emptying and decreases the esophageal diameter.25
The overall complication rate of LHM is about
6% with reported mortality of 0.1%, hence LHM
combined with partial fundoplication is considered a
safe operation.5
Data are lacking to demonstrate how many
operations are needed to ensure competency of the
surgeon performing LHM. Sharp et al. reported that in
a series of 100 operations, most of the complications
occurred in the first 50.25,37
Early recurrence of dysphagia can develop in up to
31% of cases within 12-18 months after surgery and
is usually caused by incomplete myotomy, excessive
scarring or tight anti-reflux wrap. Management of LHM
failure can usually be done conservatively by pneumatic
dilation.25,38,39
Esophagectomy
This may be necessary in cases of megaesophagus with
esophageal diameter >6 cm or if tortuosity (sigmoid
esophagus) is hindering emptying. The reconstruction
options after esophageal resection are gastric pull-up
or long segment colonic interposition. Most surgeons
prefer the gastric pull-up because it requires only one
anastomosis to be done.40
Figure 3. Barium esophagram showing sigmoid
configuration of the esophagus.
Per Oral Endoscopic Myotomy (POEM)
It seems that even as we appear to have settled some
age-old questions the equation is being changed by the
new kid on the block, per oral endoscopic myotomy,
or POEM.
Both PD and LHM are considered the “standard
of care” of achalasia treatment. Recently, POEM is
emerging as an alternative to LHM. POEM has the
advantages of minimal invasiveness of an endoscopic
procedure and the precision of a surgical myotomy.41,42
The standard POEM steps as described by Inoue et
al are (1) creation of a submucosal tunnel from 12 cm
proximal to the LES to about 2-4 cm into the stomach.
The submucosal tunnel is usually created on the anterior
esophageal wall except in post-Heller patients in
whom it is created on the posterior esophageal wall;
(2) myotomy of the circular muscle fibers starting 3-4
cm distally from the first incision and 2-4 cm into the
stomach wall; and (3) closure of the entry site by using
endoscopic clips.42
Since POEM is relatively new, only short- and
intermediate-term treatment success rates are available.
There were several studies that showed objective
improvement in esophageal function assessed by
manometry and timed barium esophagram findings
after POEM (even comparable to LHM).43
One of the main concerns with POEM, compared
with laparoscopic Heller myotomy (LHM), is that an
anti-reflux procedure is not performed concurrently. The
reported incidence of reflux following POEM reaches
higher than 50% in America and Western Europe.44
PD vs. LHM
Over the years management of achalasia has revolved
around discussion of preference for a “medical” or
surgical approach as a definitive therapy; i.e. large
balloon pneumatic dilatation (PD) versus myotomy
as the means to disrupt the dysfunctional circular
muscle of the LES. Each has its champions and its nay-
sayers; for years there has been no high level RCT to
direct treatment preference beyond opinion and “local
expertise”. The recent publication in the New England
Journal of a large multicenter prospectively randomized
trial from across Europe has shown convincingly that
the two widely used approaches are equally effective
with PD having a slight edge. Maybe the popular
approach of using PD as initial therapy and saving
myotomy as a “rescue” approach is the best. The
European experience also reminded us that PD should
be performed with step-wise balloon sizes and that
repeated dilations for recurring symptoms, even years
apart should be considered; not the “one and done”
approach of a myotomy.2
As most practicing gastroenterologists are unlikely
to see patients with achalasia very often, it is difficult for
them to maintain a level of appropriate expertise with
pneumatic dilatation as a treatment option and patients
are thus often referred for a myotomy.
Whether the inclination is for treatment of achalasia
with pneumatic dilatation or LHM it is our belief that
these patients should be referred to a specialist center
(center of excellence) where an individual or a team
actively treats patients with achalasia regularly.
The results of the European trial strongly reinforces
the suggestion that the real decision should be based on
what local expertise is available; that is, whether there
is an individual in the vicinity who has the experience
and knowledge to treat achalasia, be it by surgical or
balloon dilation.
Interestingly, the rapidly evolving technique of
high-resolution manometry has brought to light the
concept of three subtypes of achalasia. Although no
difference in outcome between Heller myotomy and PD
has been noted for patients with type I and II achalasia,
patients with type III disease seem to respond better to
Heller myotomy than to PD.45
To the neophyte, this observation is often
considered as new. To the experienced esophagologist,
however, subtyping of achalasia is just a new vision
of a well-known concept. Interestingly, the European
study was performed at a group of medical centers,
none of which used high-resolution manometry to
establish the diagnoses. Therefore, one could argue
definitively that this old disease is well recognized
and appropriately staged for therapy on the basis of
good-quality manometry of any kind, and is not a new
disease recently discovered by a new technology. Use
of subtyping, perhaps made easier by the technique of
high-resolution manometry, should continue to guide
therapy decisions for patients with achalasia.
CONCLUSION
The European multicentre study comparing pneumatic
dilation with laparoscopic Heller myotomy, along with
the author’s experience of greater than 40 years as an
“esophagologist”, established PD as the preferred
approach for initial treatment of achalasia. We think it
is appropriate to consider a referral to an esophageal
expert, for either a PD or a myotomy.
download tables, images & references